Gantry crane

ABSTRACT

A heavy duty gantry crane suitable for railroad piggyback operations. Forming the bridge is a pair of spaced apart parallel girders supported on steel legs and wheeled trucks for operating over runway rails. Interconnecting trolleys laterally positionable on the bridge operate lift forks in controllably guided horizontal and vertical planes. A pendant push-button station connected to a widely pivotal swivel boom enables one man operational control from ground level.

PATENIEB .ma 8 1874 an iv PATENTEDJAN 8 I974 SHHIWW 4 56 FIG. 8

GANTRY CRANE BACKGROUND OF THE INVENTION 1. The field of art to whichthe invention pertains generally includes the art of traveling hoists asmore specifically directed to load handling gantry type cranes.

2. Trailer-on-flat-car cargo handling, sometimes referred to in thetrade as piggyback, represents a major source of railroad revenue yet atthe same time it imposes a relatively difficult handling problem withwhich the railroads have to contend. Individual loading and unloading inthis type operation usually involves large elongated semi-trailershaving loaded gross weights of on the order of 40 tons. Equipment forhandling this magnitude of load to, for example, transfer it betweentractor and flat car not only requires adequate load carrying capacitybut also requires a maximum degree of load maneuverability to beafforded in and about the loading area. Moreover, and particularly inview of recent economic deterioration of the railroad industry, thecapital cost and reliability of such handling equipment are becomingincreasingly paramount considerations in dictating the purchased choice.

Most equipment employed for these purposes is typically of either thetruck-driven side loader type or a form of overhead gantry crane. Theformer employs front end loading imposing practical load limitations onthe device to avoid overturning while otherwise requiring vast areas ofhighly reinforced concrete foundation in and around the loading area formaneuverability. On the other hand, previously employed gantry craneshave usually been rubber tired, requiring heavily reinforced concreteribbons while otherwise characterized as utilizing complex support andoperating structures contributing to undesirably high capital cost andoperating expense. Exemplifiying gantry cranes for piggyback handlingare U.S. Pats. 3,081,884 and 3,645,406.

SUMMARY The invention relates to gantry cranes and more specifically togantry cranes particularly suitable for heavy duty service associatedwith railroad piggyback operations. In accordance herewith, maximumsimplicity is afforded to both the support and operating structureswhereby to enable capital and operating cost of such equipment to besubstantially reduced as compared to existing gantries similarlyemployed. At the same time, this result is achieved with enhancedmaneuvering flexibility accompanied by a generally greater handlingreliability while eliminating the extensive and expensive reinforcedconcrete ribbons previously required.

These results are achieved by means of the invention utilizing aconnected simple two girder bridge supported on steel legs for wheeledmobility over runway rails. Two trolleys operatively interconnected aresupported on the bridge for companion concomitant operation of oppositelift frames in carefully guided horiozontal and vertical planes. In thismanner, restrictively positive planar movement is afforded to the framesreinforced against sway that might otherwise be encountered. A pendantpush-button station suspended from an overhead hinged swivel boomenables one man control of the entire crane assembly from ground level.

It is therefore an object of the invention to provide a novel form ofgantry crane particularly'suitable for railroad piggyback operations.

his a further object of the invention to provide a novel gantry typecrane as in the last mentioned object having maximum simplicity insupport and operating structures for enabling ultimate cost reduction tothe railroad consumer.

It is a further object of the invention to provide a piggyback servicegantry crane having heavy duty capacity that affords enhancedmaneuvering flexibility with a generally greater handling reliability ascompared to such similar purpose structures of the prior art whiledecreasing rather than increasing the manufacturing complexitiesthereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric illustration ofa double bay gantry crane construction in accordance herewith;

FIG. 2 is a front elevation of the crane;

FIG. 3 is a side elevation of the crane;

FIG. 4 is a top plan view of the hoisting apparatus;

FIG. 5 is a partial enlarged plan view of the interconnecting trolleymechanism;

FIG. 6 is an enlarged front view of a lift fork vertical guidemechanism;

FIG. 7 is a partial sideview of the vertical guide;

FIG. 8 is a sectional view taken substantially along the lines of 8-8 ofFIG. 6; and

FIG. 9 is an enlarged fragmentary elevation of the swivel bottomsupport.

Referring now to the drawings and most particularly to FIGS. l3, thereis shown a gantry crane installation in accordance herewith for loadingand unloading semi-trailers 5 from railroad flat cars 6. Comprising thecrane is a rectangular shaped bridge, designated 10, formed of oppositegirders l1 and 12 latticed together spanning the work area and joined attheir ends by opposite intersecting girders 13 and 14. At each cornerformed between the intersecting girders, the bridge is supported by avertical column 18, opposite pairs of which rest on mobile trucks 19 and20. Intermediate column stabilization in a longitudinal direction isprovided by lateral beam 24. Each of the trucks includes a pair oftracking wheels 21 for engaging ground supported parallel track rails 22and 23 over which the crane is driven by means of motors M1 and M2 forlongitudinally positioning the crane as required. With the specificarrangement illustrated, the bridge spans a flat car loading andunloading bay 30 encompassing track 31 and tractor trailer receiving anddischarge bays 32 and 33 respectively. The use of separate receiving anddischarge bays in this manner for each rail car position affords minimaltrailer handling while allowing for simultaneous loading and unloadingof trailers. It is to be understood of course that the shown bayarrangement is intended only to be illustrative as exemplifying use ofthe invention but can readily be adapted otherwise in accordance withcustomer preference.

For loading and unloading semi-trailers between a tractor and flat car,a trolley assembly 38 for serving the various bays is provided withopposed inwardly facing lift frames 39 and 40. Each frame is comprisedof a pair of spaced inwardly extending forks or lips 42 of relativelyshort longitudinal length that are laterally secured to joist-likebracing 43. The bracing in turn is supported at its end by dependingrectangular guide tubes 44 vertically movable within vertical guidesupports 53. Raising and lowering of the frames is coordinated in unisonby means of hoisting assembly 38 that 3 includes trolleys 64 and 65 foroperating cables 45 and 46 extending vertically at opposite ends of eachframe. The cables are reeved about sheaves 47 and 48 respectivelysupported in a frame 49 secured within. bracing 43.

Each guide tube 44 is rigidly supported against other than verticalmovement by a vertically elongated guide support 53 fixedly secured inmatched pairs as by welding to one of hoist trolleys 64 and 65. Each ofthe guide supports 53, as can be best seen in FIGS. 6-8, is centrallyhollowed to receive a guide tube 44 affording it freedom of movement ina carefully guided vertical relation. Effecting guidance in onedirection are upper and lower oppositely positioned guide rollers 54 and55 bearing against the tube sides in the course of its movement.Vertically intermediate the latter rollers are a pair of opposite guiderollers 56 likewise bearing against the other tube sides for effectingguidance in a transverse direction. The rollers themselves are bearingmounted about stationary pins 57, 58 and S9 respectively, that extendlaterally through opposite sidewalls of their guide supports. In turnsecuring each pin in place thereat is a bolted mounting bracket 60. Bymeans of the rollers engaging the guide tubes at displaced locations,accurate vertical alignment is readily maintained against tube sway fromloading, wind or other sway inducing factors potentially encountered inoperation of such devices.

Hoisting trolley assembly 38 will now be described with additionalreference to FlGS. 4-5. Comprising the hoisting mechanism are thepreviously mentioned trolleys 64 and 65 representing master and slavetrolleys respectively. Each trolley is supported on wheel sets 66 forriding on steel rails 68 secured along the top surface of girders 11 and12. As will be understood, trolley operation is relatively coordinatedfor raising, lowering and horizontally setting the frame members duringand subsequent to load handling of a semitrailer between its tractor andflat car.

Master trolley 64, controlling frame member 39, comrises a structurallyreinforced platform 72 on which the operating components are mounted andis itself supported via wheels 66 on trolley rails 68. Lowering andelevating of the frame is effected by motor M3 operating through a gearreducer 73 for driving rotatable cable drum 74. Cables 45 and 46 extendfrom attachment at one end of the drum reeved over multiple uppersheaves 75 and 76 and multiple lower sheaves 47 and 48 respectively.Turnbuckles, not shown, receive the rope ends and facilitate levellingof the frame.

Slave trolley 65 for controlling frame 40 and interconnected withtrolley 64 likewise includes a structurally reinforced platform 80supporting the operating components and is similarly supported viawheels 66 on trolley rails 68. Raising and lowering of frame 40 iseffected by means of motor M4 operating through a gear reducer 81 fordriving rotatable cable drum 82. Cables 45' and 46' are attached to thedrum from where they extend and are reeved over multiple upper sheaves83 and 84 and multiple lower sheaves 47 and 48 respectively similarly asdescribed above for frame 39.

Movement of frames 39 and 40 horizontally as a unit and laterally onbridge for either preliminary positioning or transporting a load isgoverned by motor M6 on master trolley 64 operating through a gear case93 driving output shaft 94. The shaft in turn is connected to a wheelpair of set 66 such that when the motor is energized causes the trolleysto traverse .over their supporting girders. To effect relative movementof frames 39 and 40 toward and away from each other for receiving ordischarging a load, the trolleys are interconnected via a lead screw 86operative by a torque and brake motor M5 through a gear reducer 87. Abearing assembly 88 on the lead screw is gimbal mounted to the mastertrolley whereas an Acme nut 89 on the lead screw is gimbal mounted tothe slave trolley. Operation of motor M5 for rotating the leadscrew-causes movement of the slave trolley relatively toward and awayfrom the master trolley. Adjustable stops 90 and 9] limit travel of theslave trolley to on the order of about 4 feet. By limiting the driveforce of motor M5 to about lbs., trailer oversqueezing or inadvertentopening of the frames when loaded are thereby prevented.

For operating the crane, there is provided a pushbutton station 96suspended from a swivel boom 97 that is hingedly supported from thefront face of a guide support 53 in the manner best illustrated in FIG.9. As thereshown, boom 97 is formed of tubular components 102, 103 and104 that merge toward the boom front and are joined at the rear by avertical tube 105. The entire unit is supported on hinge pins 108 and109 mounted onto the front face of the guide support. Pushbutton station96 is suspended to within reasonable reach of an operator on the groundand by means of approximately pivot travel afforded by the swivel boom,the operator has complete visible access to the frame positions foroperating the various components as required. Circuiting employed iswell known whereby power from a suitable source under control of thepush-button station is transmitted to the various operating componentsvia three wire festooned cable 1 10. Preferably, two speed hoisting isprovided for faster movement when unloaded than when loaded.

By the above description there is disclosed a novel gantry craneapparatus suitable for heavy duty railroad piggyback operations. Arelatively simple rectangular bridge construction of parallel girderssupports the operating trolleys for transverse movement. The bridgeitself is operative over runway rails for proper positioning relative toflat cars and semi-trailers received in their respective operating bays.Supported movement is restricted to the horizontal and vertical planesover which the lift frames are accurately guided to insure properpositioning and support of the semi-trailers to be handled thereby whileminimizing or avoiding sway that might otherwise be encountered duringthe handling operation. By virtue of the near ground position of pendantcontrol 96, the entire operation can be governed by a single operator atground level able to visibly inspect all loading sides before hoistingis initiated. With this arrangement, maximum simplicity is afforded toboth the crane support and its operating structure in order to obtainincreasingly favorable manufacturing costs that can be passed on to theconsumer. At the same time, the obtained cost reduction is achieved withenhanced maneuvering flexibility accompanied by a generally greaterhandling reliability while eliminating the expensive concrete supportaprons previously required for similar purpose structures of the priorart.

Since many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the drawings and specification shall be interpreted asillustrative and not in a limiting sense. i

The embodiments of the invention in which exclusive property orprivilege is claimed are defined as follows;

1. A gantry crane adapted for semi-trailer piggyback railroad servicecomprising in combination:

a. a bridge for spanning a semi-trailer piggy-back work area to beserviced;

b. mobile bridge support means for locating the bridge longitudinallywithin the work area;

c. a pair of oppositely extending lift frames individually supportedfrom said bridge with each lift frame of said pair being positionableinto and out of underlying support relation with a semi-trailer to berelocated within the work area;

d. first drive means for presettable vertical positioning of said liftframes into and out of said support relation;

e. second drive means for presettable horizontal positioning of saidlift frames on said bridge relative to each other into and out of saidsupport relation;

f. third drive means for locating said positioned lift frames on saidbridge transversely within the work area between said bridge supportmeans for transporting a semi-trailer in support relation on said liftframes; and

g. guide means effective for maintaining a substantially rigidtransverse planar relation between the paths of vertical and horizontalmovement incurred in the positioning of said lift frames by said firstand second drive means.

2. A gantry crane according to claim 1 in which said first drive meansincludes first and second trolley means on said bridge each operativefor vertically positioning one lift frame of said pair in coordinatedrelation to the other.

3. A gantry crane according to claim 2 in which said lift frames includehorizontal lip members and noncircular vertical tubes connected to saidlip members for effecting said underlying support relation and saidguide means include vertically extending tube guides secured to saidfirst and second trolley means to receive and vertically guide saidtubes in the course of vertical lift frame positioning by said trolleymeans.

4. A gantry crane according to claim 3 in which said tubes arerectangular in cross-section and said tube guides include verticallydisplaced guide rollers in surface guiding engagement against oppositeexterior surfaces of said tubes.

5. A gantry crane according to claim 3 in which said third drive meansis operatively connected to said first and second trolley means foreffecting trolley traversal of said bridge.

6. A gantry crane according to claim 3 in which said guide meansincludes horizontal guide rails on said bridge commonly supporting saidfirst and second trolley means for horizontal positioning by said seconddrive means.

7. A gantry crane according to claim 6 including a lead screwinterconnecting said first and second trolley means and operative bysaid second drive means.

8. A gantry crane according to claim 7 including pendant control meansfor selective operator actuation of said first, second and third drivemeans and a hinge connected swivel boom supporting said pendant controlmeans for operator positioning within a predetermined arcuate range ofoperator viewing.

9. A gantry crane according to claim 8 in which said mobile bridgesupport means includes mobile trucks adapted for rail travel.

10. A gantry crane according to claim 2 in which said guide meansincludes horizontal guide rails on said bridge commonly supporting saidfirst and second trolley means for horizontal positioning by said seconddrive means.

1. A gantry crane adapted for semi-trailer piggyback railroad servicecomprising in combination: a. a bridge for spanning a semi-trailerpiggy-back work area to be serviced; b. mobile bridge support means forlocating the bridge longitudinally within the work area; c. a pair ofoppositely extending lift frames individually supported from said bridgewith each lift frame of said pair being positionable into and out ofunderlying support relation with a semi-trailer to be relocated withinthe work area; d. first drive means for presettable vertical positioningof said lift frames into and out of said support relation; e. seconddrive means for presettable horizontal positioning of said lift frameson said bridge relative to each other into and out of said supportrelation; f. third drive means for locating said positioned lift framEson said bridge transversely within the work area between said bridgesupport means for transporting a semi-trailer in support relation onsaid lift frames; and g. guide means effective for maintaining asubstantially rigid transverse planar relation between the paths ofvertical and horizontal movement incurred in the positioning of saidlift frames by said first and second drive means.
 2. A gantry craneaccording to claim 1 in which said first drive means includes first andsecond trolley means on said bridge each operative for verticallypositioning one lift frame of said pair in coordinated relation to theother.
 3. A gantry crane according to claim 2 in which said lift framesinclude horizontal lip members and non-circular vertical tubes connectedto said lip members for effecting said underlying support relation andsaid guide means include vertically extending tube guides secured tosaid first and second trolley means to receive and vertically guide saidtubes in the course of vertical lift frame positioning by said trolleymeans.
 4. A gantry crane according to claim 3 in which said tubes arerectangular in cross-section and said tube guides include verticallydisplaced guide rollers in surface guiding engagement against oppositeexterior surfaces of said tubes.
 5. A gantry crane according to claim 3in which said third drive means is operatively connected to said firstand second trolley means for effecting trolley traversal of said bridge.6. A gantry crane according to claim 3 in which said guide meansincludes horizontal guide rails on said bridge commonly supporting saidfirst and second trolley means for horizontal positioning by said seconddrive means.
 7. A gantry crane according to claim 6 including a leadscrew interconnecting said first and second trolley means and operativeby said second drive means.
 8. A gantry crane according to claim 7including pendant control means for selective operator actuation of saidfirst, second and third drive means and a hinge connected swivel boomsupporting said pendant control means for operator positioning within apredetermined arcuate range of operator viewing.
 9. A gantry craneaccording to claim 8 in which said mobile bridge support means includesmobile trucks adapted for rail travel.
 10. A gantry crane according toclaim 2 in which said guide means includes horizontal guide rails onsaid bridge commonly supporting said first and second trolley means forhorizontal positioning by said second drive means.